China’s central bank has burnt through nearly half a trillion dollars in foreign reserves to support its currency since August, despite criticism that it has betrayed its commitment to let market forces drive the exchange rate.

自去年8月以来，中国央行已烧掉了近5000亿美元外汇储备以支撑人民币汇率——尽管有批评意见认为该行背弃了让市场力量在更大程度上决定汇率的承诺。

Sources close to the central bank said the intervention, while costly, had been necessary to maintain economic confidence and prevent a disorderly depreciation that could have had ripple effects far beyond the currency.

与这家央行关系密切的人士表示，这一干预行为尽管代价巨大，但对于维护经济信心和阻止人民币无序贬值是必要的。无序贬值可能会产生远超人民币本身的涟漪效应。

The People’s Bank of China has spent about $473bn of its foreign exchange reserves since it surprised global markets last August by changing the way it set its daily guidance rate for the currency, according to Financial Times estimates based on official data.

去年8月，中国央行改变了设定每日人民币汇率中间价的方式，震惊全球市场。自那以来，据英国《金融时报》基于官方数据的估计，中国央行已花掉了大约4730亿美元的外汇储备。

Fears that China would permit or actively encourage a sharp devaluation led to a wave of renminbi selling after the move.

在中国央行这一改革之后，对中国可能允许或积极鼓励人民币大幅贬值的担忧，引发了一轮人民币抛售潮。

“The most important factor is confidence, both globally and within China,” said a central bank official. “The cost of intervention in terms of reserves has been high, but this policy can’t be evaluated just in terms of numbers. Once confidence is lost it can’t be easily restored. Then a lot of bad things can happen.”

一名央行官员表示：“不论对全球还是中国国内来说，信心都是最重要的因素。用外储干预的代价很高，但这一政策的价值不能只用数字来衡量。信心一旦丧失就很难恢复。届时会发生很多糟糕的事情。”

PBoC officials knew that changing the way the central bank set the daily “fix” would unleash pent-up depreciation pressure, but they underestimated the intensity of the market reaction, according to analysts.

按照分析师的说法，中国央行官员事先知道改变人民币中间价设定方式可能释放被抑制的人民币贬值压力，不过他们低估了市场反应的激烈程度。

A move that might have been expected to produce a 5 per cent downward adjustment quickly threatened to spark a 10 or 20 per cent rout in a matter of days. Such an uncontrolled devaluation could have undermined the broader financial system by inciting investors to dump renminbi assets en masse.

这一原本预期会导致汇率下调5%的举措，很快就演变成了在几天内引发10%到20%汇率下挫的威胁。这种不受控制的贬值，可能会刺激投资者竞相抛售人民币资产，从而削弱整体金融体系。

The International Monetary Fund is likely to address exchange rate volatility, among other financial risks, when David Lipton, its deputy managing director, presents the fund’s annual financial stability report on China today in Beijing.

今天，国际货币基金组织(IMF)副总裁戴维•利普顿(David Lipton)将在北京发布IMF有关中国的年度金融稳定性报告。届时，除了其他金融风险，该机构还可能提到汇率波动问题。